Effect of Ageing in the Mating Behaviour Sequence of Osmia cornuta Latr. (Hymenoptera: Megachilidae)

SIMPLE SUMMARY: The mason bee Osmia cornuta is largely used for orchard crop pollination worldwide, both enhancing the maintenance of health ecosystems and providing economic benefits for human society. A deepening of the reproductive biology of O. cornuta could refine the management techniques of these pollinators. In the present study, the behavioural sequence of O. cornuta mating is described by using Marcov analysis, which revealed the occurrence of repeated, stereotyped, and regular sequences of behavioural units, including two types of copulations, i.e., short and long. The results reported in this paper support the hypothesis that ageing could negatively influence the success of reproduction in mason bees. ABSTRACT: Osmia cornuta Latr. is largely managed worldwide for the pollination of orchard crops, playing a key role in the maintenance of healthy ecosystems and ensuring economic and social benefits for human society. The management techniques of this pollinator include the possibility of delaying emergence from cocoons after diapause, allowing for the pollination of later-blooming fruit crops. In this study, the mating behaviour of bees emerging at the natural time (Right Emergence Insects) and of late-emerged bees (Aged Emergence Insects) was described in order to test if a delay in emergence could affect the mating sequence of O. cornuta. Markov analysis of the mating behaviour revealed the occurrence of antenna motion episodes that were repeated in a stereotyped manner at regular intervals during the mating sequence of both Right Emergence Insects and in Aged Emergence Insects. Pouncing, rhythmic and continuous emission of sound, motion of antennae, stretching of the abdomen, short and long copulations, scratching, inactivity, and self-grooming were identified as the stereotyped behavioural units of a behavioural sequence. The occurrence of short copulations, the frequency of which increased with the age of bees, could lead to a failure in the reproduction of the mason bee.